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/*
* RTP packetization for Xiph audio and video
* Copyright (c) 2010 Josh Allmann
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "rtpenc.h"
/**
* Packetize Xiph frames into RTP according to
* RFC 5215 (Vorbis) and the Theora RFC draft.
* (http://svn.xiph.org/trunk/theora/doc/draft-ietf-avt-rtp-theora-00.txt)
*/
void ff_rtp_send_xiph(AVFormatContext *s1, const uint8_t *buff, int size)
{
RTPMuxContext *s = s1->priv_data;
AVStream *st = s1->streams[0];
int max_pkt_size, xdt, frag;
uint8_t *q;
max_pkt_size = s->max_payload_size - 6; // ident+frag+tdt/vdt+pkt_num+pkt_length
// set xiph data type
switch (*buff) {
case 0x01: // vorbis id
case 0x05: // vorbis setup
case 0x80: // theora header
case 0x82: // theora tables
xdt = 1; // packed config payload
break;
case 0x03: // vorbis comments
case 0x81: // theora comments
xdt = 2; // comment payload
break;
default:
xdt = 0; // raw data payload
break;
}
// Set ident.
// Probably need a non-fixed way of generating
// this, but it has to be done in SDP and passed in from there.
q = s->buf;
*q++ = (RTP_XIPH_IDENT >> 16) & 0xff;
*q++ = (RTP_XIPH_IDENT >> 8) & 0xff;
*q++ = (RTP_XIPH_IDENT ) & 0xff;
// set fragment
// 0 - whole frame (possibly multiple frames)
// 1 - first fragment
// 2 - fragment continuation
// 3 - last fragment
frag = size <= max_pkt_size ? 0 : 1;
if (!frag && !xdt) { // do we have a whole frame of raw data?
uint8_t *end_ptr = s->buf + 6 + max_pkt_size; // what we're allowed to write
uint8_t *ptr = s->buf_ptr + 2 + size; // what we're going to write
int remaining = end_ptr - ptr;
assert(s->num_frames <= s->max_frames_per_packet);
if (s->num_frames > 0 &&
(remaining < 0 ||
s->num_frames == s->max_frames_per_packet ||
av_compare_ts(s->cur_timestamp - s->timestamp, st->time_base,
s1->max_delay, AV_TIME_BASE_Q) >= 0)) {
// send previous packets now; no room for new data, or too much delay
ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
s->num_frames = 0;
}
// buffer current frame to send later
if (0 == s->num_frames)
s->timestamp = s->cur_timestamp;
s->num_frames++;
// Set packet header. Normally, this is OR'd with frag and xdt,
// but those are zero, so omitted here
*q++ = s->num_frames;
if (s->num_frames > 1)
q = s->buf_ptr; // jump ahead if needed
AV_WB16(q, size);
q += 2;
memcpy(q, buff, size);
q += size;
s->buf_ptr = q;
return;
} else if (s->num_frames) {
// immediately send buffered frames if buffer is not raw data,
// or if current frame is fragmented.
ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
}
s->timestamp = s->cur_timestamp;
s->num_frames = 0;
s->buf_ptr = q;
while (size > 0) {
int len = (!frag || frag == 3) ? size : max_pkt_size;
q = s->buf_ptr;
// set packet headers
*q++ = (frag << 6) | (xdt << 4); // num_frames = 0
AV_WB16(q, len);
q += 2;
// set packet body
memcpy(q, buff, len);
q += len;
buff += len;
size -= len;
ff_rtp_send_data(s1, s->buf, q - s->buf, 0);
frag = size <= max_pkt_size ? 3 : 2;
}
}
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